1. Technical Field
This application generally relates to a data storage system, and more particularly to techniques used with notification of events in a data storage system.
2. Description of Related Art
Computer systems may include different resources used by one or more host processors. Resources and host processors in a computer system may be interconnected by one or more communication connections. These resources may include, for example, data storage devices such as those included in the data storage systems manufactured by EMC Corporation. These data storage systems may be coupled to one or more host processors and provide storage services to each host processor. Multiple data storage systems from one or more different vendors may be connected and may provide common data storage for one or more host processors in a computer system.
A host processor may perform a variety of data processing tasks and operations using the data storage system. For example, a host processor may perform basic system I/O operations in connection with data requests, such as data read and write operations.
Host processor systems may store and retrieve data using a storage device containing a plurality of host interface units, disk drives, and disk interface units. Such storage devices are provided, for example, by EMC Corporation of Hopkinton, Mass. and disclosed in U.S. Pat. No. 5,206,939 to Yanai et al., U.S. Pat. No. 5,778,394 to Galtzur et al., U.S. Pat. No. 5,845,147 to Vishlitzky et al., and U.S. Pat. No. 5,857,208 to Ofek. The host systems access the storage device through a plurality of channels provided therewith. Host systems provide data and access control information through the channels to the storage device and storage device provides data to the host systems also through the channels. The host systems do not address the disk drives of the storage device directly, but rather, access what appears to the host systems as a plurality of logical disk units. The logical disk units may or may not correspond to the actual disk drives. Allowing multiple host systems to access the single storage device unit allows the host systems to share data stored therein.
Different tasks may be performed in connection with a data storage system. For example, management tasks may be performed in connection with one or more data storage systems. A management console or station may be used to monitor the data storage systems. The management console may be provided with updates or changes regarding the data storage systems. One existing technique used in connection with providing the updates to the management console system may characterized as a polling or reporting technique. Each of the data storage systems may execute instructions which report updates to the management console at regular periodic intervals.
The foregoing technique may have existing drawbacks. The reporting by each data storage system at each interval may consume an unacceptable amount of system bandwidth and other data storage system resources. The number of incoming messages to be processed by the management console increases with the number of data storage systems and may eventually saturate or “flood” the management console and associated connection used for reporting. Additionally, reporting at periodic intervals means that any reported updates or events take at least until the next interval to be communicated to the management console. Further, more time elapses before the management console completes processing the reports once they have been received. As a result, the total time which elapses between the occurrence of an event until that event is eventually received by a system manager at the management console may not be an acceptable amount of time. The management console may be displaying, for example, stale or outdated information or may be informed about an event within an unacceptable amount of time.
Thus, it may be desirable to have an efficient technique for reporting events and updates regarding one or more data storage systems in a timely manner. It may be desirable that the technique be scalable for use with a varying number of data storage devices and events occurring therein.